# Data Dictionary - Global Earthquake Catalog (USGS ANSS ComCat, M≥4.5) - every significant quake since 2000, cleaned

**Units:** stated per column in the descriptions below (this is a relational table; columns mix units).

| column | type | description |
|---|---|---|
| `event_id` | str | USGS event identifier (primary key) |
| `time` | str | Origin time (UTC, YYYY-MM-DD HH:MM:SS) |
| `latitude` | float | Epicentre latitude (decimal degrees) |
| `longitude` | float | Epicentre longitude (decimal degrees) |
| `depth_km` | float | Hypocentre depth (km) |
| `magnitude` | float | Event magnitude |
| `mag_type` | str | Magnitude type (mww, mb, ml, …) |
| `place` | str | Human-readable location description |
| `event_type` | str | Event type (earthquake, quarry blast, …) |
| `felt_reports` | int | Count of 'Did You Feel It?' felt reports |
| `cdi` | float | Community-determined intensity (max reported) |
| `mmi` | float | Modified Mercalli shaking intensity (instrumental) |
| `alert` | str | PAGER alert level (green/yellow/orange/red) |
| `tsunami` | int | Tsunami flag (1 = tsunami-associated region) |
| `significance` | int | USGS significance score (0-1000+) |
| `azimuthal_gap` | float | Largest azimuthal station gap (degrees) |
| `rms` | float | RMS travel-time residual (s) |
| `network` | str | Contributing network id |
| `n_stations` | int | Number of seismic stations used |
| `status` | str | Review status (reviewed / automatic) |

*Source: U.S. Geological Survey - ANSS Comprehensive Catalog (ComCat).*